Table 1. Diagnostic criteria for cardiac sarcoidosis from guidelines of Japanese Ministry of Health and Welfare and Heart Rhythm Society expert consensus statement.

Japanese Ministry of Health and Welfare recommendations6)
	(1) Patient group diagnosed based on histological findings
		Histopathological findings include non-necrotizing epithelioid granuloma in the myocardium, and the patient is found to exhibit histopathological changes in organs other than the heart or by clinical signs.
	(2) Patient group diagnosed based on clinical signs
		Histopathological findings do not include non-necrotizing epithelioid granuloma in the myocardium. Patients are diagnosed with cardiac sarcoidosis when they have histopathological changes in organs other than the heart or by clinical signs, together with the following conditions and one or more of six primary diagnostic criteria.
		1. Two or more major criteria
		2. One major and two or more minor criteria
			1) Major criteria
				(a) Severe atrioventricular block
				(b) Ventricular septal thinning localized at the basal portion
				(c) Abnormal uptake of 67Ga in the heart on 67Ga scintigraphy
				(d) Left ventricular contraction failure (left ventricular ejection fraction less than 50%)
			2) Minor criteria
				(a) Abnormal electrocardiogram: ventricular arrhythmia (ventricular tachycardia, multi-origin or frequent ventricular premature beats), right bundle branch block, axis deviation, or abnormal Q waves
				(b) Echocardiography: localized abnormal left ventricular wall motion, or morphological abnormalities (ventricular aneurysm and/or ventricular wall thickening)
				(c) Nuclear medicine techniques: abnormal blood flow on myocardial perfusion scintigraphy (thallium-201 chloride or technetium-99m methoxyisobutylisonitrile, technetium-99m tetrofosmin)
				(d) Abnormal imaging on delayed gadolinium-enhanced CMR
				(e) Endomyocardial biopsy: Moderate or more severe myocardial interstitial fibrosis and mononuclear cell infiltrates
Heart Rhythm Society expert consensus recommendations5)
	(1) Histological diagnosis from myocardial tissue
		Cardiac sarcoidosis is diagnosed in the presence of non-caseating granuloma on histological examination of myocardial tissue with no alternative cause identified (including negative organismal stains if applicable).
	(2) Clinical diagnosis from invasive and non-Invasive studies
		It is probable* that there is cardiac sarcoidosis if:
			a) There is a histological diagnosis of extra-cardiac sarcoidosis
			and
			b) One or more of following is present
				• Steroid +/− immunosuppressant responsive cardiomyopathy or heart block
				• Unexplained reduced left ventricular ejection fraction (< 40%)
				• Unexplained sustained (spontaneous or induced) ventricular tachycardia
				• Mobitz type II 2nd degree heart block or 3rd degree heart block
				• Patchy uptake on dedicated cardiac PET (in a pattern consistent with cardiac sarcoidosis)
				• Late gadolinium enhancement on CMR (in a pattern consistent with cardiac sarcoidosis)
				• Positive gallium uptake (in a pattern consistent with cardiac sarcoidosis)
			and
			c) Other causes for the cardiac manifestation(s) have been reasonably excluded
			*In general, ‘probable involvement’ is considered adequate to establish a clinical diagnosis of cardiac sarcoidosis.

CMR: cardiac magnetic resonance, PET: positron emission tomography.